Furnace observation window



INVENTORS.

M N 1w fiN UM RK M D R m ww ER 5 6 L. D. BRUCE ETAL FURNACE OBSERVATIONWINDOW Filed Oct. 25, 1962 2% 'llll irlie-#4115 Aug. 25, 1964 FIG. 2

United States Patent 3,145,705 FURWACE OBSERVATION WINDOW Lester D.Bruce and George Parmakian, Worcester, Mass, assignors to Riley StokerCorporation, Worcester, Mass., a corporation of Massachusetts Filed Oct.25, 1962, Ser. No. 233,013 1 Claim. (Cl. 126193) This invention relatesto a furnace observation window and, more particularly, to apparatusarranged to permit the operator of a stream generating unit or the liketo examine the interior of the furnace to observe combustion conditions.

It is common practice in the manufatcure of steam generating units toprovide a number of windows located at various points in the unit topermit the observation of conditions within the furnace. These windowsare usually provided with a glass panel sometimes protected by a metalscreen and sometimes tinted to cut down glare from the furnace. In anycase, the radiation from the furnace is extremely great and the directcontinuous impingement of such radiation on the glass and other elementsin the window soon causes them to become inoperative. Furthermore,although air flow is often used to keep the window clean and to cool theglass, nevertheless, under ordinary furnace conditions a considerableamount of dust can accumulate inside of the window housing and itfrequently becomes necessary to remove the cover and clean out the dust.This can usually only be done when the furnace is shut down and, sinceit is uneconomical to shut down the furnace only to clean observationwidows, it is not always convenient to clean the windows when it seemsto be necessary. These and other difficulties experienced with the priorart devices have been obviated in a novel manner.

It is, therefore, an outstanding object of the invention to provide afurnace observation window in which dust does not accumulate.

Another object of this invention is the provision of a furnaceobservation window in which glass and other delicate elements areprotected from radiation when the window is not in use.

A further object of the present invention is the provision of a furnaceobservation window having a protective cover entirely contained within agas-tight enclosure.

With these and other objects in view, .'as will be apparent to thoseskilled in the art, the invention resides in the combination of partsset forth in the specification and covered by the claims appendedhereto.

The character of the invention, however, may be best understood byreference to one of its structural forms as illustrated by theaccompanying drawings in which:

FIG. 1 is a front elevation view of a furnace observation windowembodying the principles of the present invention;

FIG. 2 is a sectional view of the invention taken on the line II-II ofFIG. 1;

FIG. 3 is a vertical sectional view of the invention taken on the lineIIIIII of FIG. 1; and

FIG. 4 is an enlarged sectional view of a portion of the invention takenon the line IV-IV of FIG. 1.

The furnace observation window is shown as consisting of a main frame 1of generally cylindrical form and a door 2 extending tranverselythereof. The door slides over an orifice frame 3 also located within theframe and held within the frame by machine screws 4. A cover 5 is boltedover the outside of the frame and a shaft 6 extends through the coverinto the main frame for attachment to the door 2. A split locking ring 7holds the shaft 6 within the bore of the door 2, and a 3,145,705Patented Aug. 25, 1964 packing S underlies the locking ring to providefor rotation with a gas-tight construction.

A bushing 9 extends around the shaft 6, while a pin 10 extends throughthe shaft to lock it in place. An adjusting flange 11 is mounted on theshaft 6 at the outside to permit the adjustment of a torsion spring 12which is located on the exterior of the shaft between the flange 11 anda handle 13 to bias the handle to the position in which the door 2covers the orifice frame 3. The handle 13 is provided with a spring grip14. A pin 15 extends through the handle 13 into the shaft 6 to lock thehandle in place. A gasket 16 is located in the cover 5 and seals theglass 17 which is of a heatresistant type. The glass is locked in placeby a spring clip glass retainer 18 held by lock washers 19 and machinescrews 20. A screen 21 is held in place by a screen retainer ring 22mounted on the exertior of the cover 5. A cover gasket 24 is providedbetween the cover and the frame 1 and the cover is held in place bybolts 25. Extending from the frame 1 is a pipe fitting 26 adapted to beconnected to a source of pressure air.

The frame 1 is provided with an elongated tubular portion which isadapted to be mounted in the furnace wall and within this portion ismounted an insulating sleeve 27. The orifice frame 3 is provided with abore 28 which is slightly smaller than the bore through the insulatingsleeve. This orifice frame is provided with a shoulder having a radialsurface 29 over which the plate-like door 2 slides as it moves about theaxis of the shaft 6. Extending upwardly from the top of the frame is asecondary body 31 having a thin interior recess 32 in which the doorresides entirely out of the passage defined by the bore 28.

The operation of the invention will now be readily understood in view ofthe above description. By operating the handle 13 to rotate the shaft 6counterclockwise, as it is observed in FIG. 1, the door 2 will rotateabout the axis of the shaft 6 and enter the recess 32 in the secondarybody 31. At that time, the operator is free to look through the screen21 through the glass 17 through the bore 28 and through the furnace wallinto the interior thereof. A release of the handle 13 will cause thedoor 2 to fall back into place not only of the action of gravity butalso because of the action of the torsion spring 12. At all times airenters the housing through the fitting 26 and flows into the furnaceover the surface of the insulating sleeve 27, thus maintaining theobservation window dust free. At the same time, when in operativeposition, the door 2 seals against the radial surface 29 and keeps thedust and heat away from the glass 17 and the surrounding areas.

It is obvious that minor changes may be made in the form andconstruction of the invention without departing from the material spiritthereof. It is not, however, desired to confine the invention to theexact form herein shown and described, but it is desired to include allsuch as properly come within the scope claimed.

The invention having been thus described, what is claimed as new anddesired to secure by Letters Patent is:

A furnace observation window, comprising (a) a main frame of generallycylindrical form adapted to be mounted in an opening in the furnace Walland having an axial passage extending therethrough,

(b) a cover carrying a glass plate mounted on the frame in gas-tightrelationship over the outer end of the passage,

(0) an orifice plate mounted in the frame and having a bore extendingtherethrough, the plate having an axially-extending annular shoulderdefining a surface extending radially outwardly from the bore,

3 4 (d) a plate-like door extending transversely of the (g) afin-likesecondary body extending upwardly from passage and mounted in the body,the main frame transversely of the passage and (e) an axial pivot onwhich the door is mounted for having a thin recess for receiving the(1001' Whfifl sliding movement on an axial pivot over the said it is inthe Said Second Positionradial surface of the shoulder from a firstposi- 5 References Cited in the file of this patent tion in the passageto a second pos1t1on entirely removed from the passage 2908 254 i t 1 tl PATENTSO t 13 1959 means sn 1 in air under ressure to the frame .angoe a C inwardly fl goof, and P 2,926,658 Llgon Mar. 1, 1960 3,004,502Hibner Oct. 17, 1961

